BBC Micro

A computer commissioned by the BBC and made by Acorn, in around 1981. It's aim was to promote computer literacy, and thousands of programmers learnt to code on a "Beeb".

The original came in two flavours, the Model A (16k) and Model B (32k).&It was highly expandable though, and was still being used in schools and small businesses many, many years later. The Beeb was the machine Elite was written on, amongst many other excellent computer games.

Wonderful 8 bitcomputer by Acorn. Very nice BASIC interpreter, a whopping 32k of RAM, and endlessly hackable. It had some very nice games, even if a lot of them were just copies of Spectrum games. You could interface a BBC to just about anything - there was even an option for a second processor. Very popular with schools - I was in charge of them at mine :). Singlehandedly responsible for turning me, and many others no doubt, into a geek. Get an emulator from http://www.nvg.ntnu.no/bbc/ , and see this marvellous machine in all its glory.

Except one. Acorn Computers, after the modest success of its previous computer the Atom (nice for the time, but definitely a hobbyist's toy), had plans for their next machine, codenamed the Proton, which they felt they could adapt to meet the BBC's requirements. But the BBC was by now feeling pressed for time: would Acorn care to demonstrate a prototype for them by Friday?

In a show of managerial politics which has become legendary, Hermann Hauser, co-founder of Acorn, told each of his two chief engineers Roger Wilson and Steve Furber that the other had already agreed that it was possible to build a working prototype for the BBC in three days. Professional pride forced them to accept the challenge, and it was done. Thus it came about that the first BBC Micro was put together in less than a week.

So what was so remarkable about the BBC Micro? For one thing, it was fast. It had a 4MHz bus, where the 6502a processor memory access at 2MHz interleaved with the 6845video chip memory access at 2MHz. Yes, you read right: that was a 2MHz processor, at a time when all the competition had 1MHz processors. And that 2MHz CRTC access meant 1-bit colour at 640x256, or 4-bit colour at 160x256, all without slowing down the processor. Of course, a fast bus meant fast memory—the top-of-the-line 150ns chips required pushed the price way up, one reason why the BBC was available in your choice of the rather expensive Model B with 32k RAM (£399) and the crippled Model A with 16k (£299).

For another thing, it was versatile. The 16k BASICROM included not only one of the best versions of BASIC out there, allowing procedure/function calls by name rather than line number, distinguishable (and dynamically declarable) real, integer and string types, indirection operator syntax to treat memory locations as variables, and other unique enhancements: it also had a built-in 6502 assembler, so the barrier to everyone and their dog writing fast machine-code graphics was not £100 development software but rather a £10 manual, easily available from your local bookshop in those bygone days. Of course this fertile development environment, combined with the BBC's endorsement, quickly gave rise to the body of software which kept the BBC micro popular for years to come.

For yet another thing, it was upgradable. Acorn's vision was that you would never need to replace the computer: as more technology became available you would simply plug it into one of the thoughtfully provided expansion ports. Thus there were two parallel ports—one for your printer, one for whatever the hell else—, an analogue port (whatever happened to those?) for your niftyanalogue joysticks, an RS423 port (I used mine for uploading all my crap to my next computer), plus spaces on the circuit board where you could put in a floppy diskinterface, Econet network capabilities, and even a speech synthesiser. And in case they'd missed anything, there was an expansion port with access to the system bus—the clock speed slowed to 1MHz when you were using it in case your flaky add-on hardware couldn't hack the bleeding-edge 2MHz processor speed—and most important of all, the Tube®, which Acorn were so proud of they registered it as a trademark. The Tube® was the reason your BBC Micro would never obsolesce. When you wanted to use a more powerful processor (which at the time meant the Notional Semidestructor16032) or a different operating system (which meant CP/M, the emerging Z80-based standard), you would simply buy a second processor unit from Acorn—essentially a headless computer which communicated via the Tube®, a high-speed data bus—and your flash new computer would do the computations you desired while your trusty BBC handled the i/o and other tedious housekeeping tasks which would have wasted your second processor's time. After all, the client-server model had worked in industry for decades. Unfortunately, Acorn didn't foresee the home computer market growing in directions (games, windowing systems) for which the BBC's graphics capability would be inadequate.

So how did the BBC fare in the real world? Between the BBC branding, and its total dominance of the educational software market leading to its reassuring presence in almost every school, many British parents were persuaded to fork out for one. The BBC also sold well in some of Europe, especially the Nordic countries, and the Commonwealth, but never broke into the big American market. A broad selection of games appeared—not as many as for the C64 and Spectrum which had far more backing in America, but quite enough to establish the machine solidly. Some were conversions, but then again some absolute classics (notably Elite, also Thrust and Repton) were first created on the BBC and then ported to other platforms of the time.

Hardware add-ons also proliferated—to some extent. Disk drives, printers and joysticks were of course available, but second processors never took off, for the reasons mentioned above and because of the vicious circle of compatibility—no-one writes software for machines no-one buys, and no-one buys machines with no software. Thus a few people who really wanted to upgrade their 2MHz to 3MHz bought the 6502 second processor, which according to Acorn was compatible with “legally written” BBC software (i.e. not games), and almost no-one bought the alternative processors. (If you have a 16032 second processor at home, look after it: they're very rare.) Without this upgrade route which Acorn had been counting on, even adding more memory was a nightmare because the 6502 could only address 64k, and Acorn had already supplied a comprehensive 16k OS ROM and 16k BASIC ROM. The most common memory enhancement, and the one used in Acorn's compatible 1986 machine the BBC Master, was to add up to four 16k RAM blocks which could be swapped in instead of BASIC. Of course these couldn't be read directly from BASIC, but the BBC Master was popular enough that various games were written to make use of them.